Steering mechanism for vehicles, etc.



July 28, 1936. w. o. TAIT, JR

STEERING MECHANISM FOR VEHICLES ETC Rummy un www Filed Nov. ll,

Patented July 28, 1936 STEERING ME VEmCLES, ETC.

William 0. Tait, Jr., Crestwood, N. Y., :es

ignor to Sheldon Hydraulic Corporation, New York, N. Y., a corporationof New York Application November 11, 1930, Serial No. 494,916

2 Claims. (Cl. 121-41) My invention relates to power control of mechanical operations where the amplitude, speed and direction of motionare variable and where power control would be advantageous to augment gcontrolling impulses of electrical, mechanical or manual origin.

One object of the device is to permit the application of power toaccomplish useful work in such a manner that the amount of motion, speedof motion and direction of the coacting mechanism will be at all timessubject `to a controlling force.

Another object is to provide means whereby the controlling force maysupplement the source of power.

A further object is to provide means whereby the controlling force mayaccomplish the work of itself in event of the failure of the source ofpower.

A still further object is to provide means whereby the shift from poweroperation to operation by means of the controlling force, as might bedesirable in the event of failure of the source of power as abovementioned, shall be instantaneous, automatic and involve no mechanical,electrical or manual operations whatsoever, nor thought or volition onthe part of the operator if the controlling force be of human agency.

The device has an extremely wide iield of application including thesteering of motor vehicles and marine craft, opening and closing doors,training guns, operating the controls of aeronautical craft and suchoperations where manual control may be inadequate or slow.

The power for this device is derived from a source of pressure which maybe gaseous or liquid. Under gaseous pressure operation, the exhaust isnormally to the atmosphere. Under liquid pressure operation the exhaustis normally to some suitable receptacle for the preservation andreclamation and re-use of the liquid.

For illustrative purposes my device is shown in the accompanying drawingas applied to the steering mechanism of an automobile utilizing liquidunder pressure as the power source.

4 Fig. 1 shows a side elevation and partial section of my device asapplied to the steering mechanism of an automobile with the powercontrol valve in the closed position and in dotted lines, the initialvalve opening when the steering wheel is moved to make a left turn.

Fig. 2 is an enlarged section showing the relative positions of thepiston and valve in the open position of Fig. 1.

Fig. 3 is a cross section on the plane of the line 3-3 of Fg. 2.

Fig. 4 is a. cross section on. the plane of the line dfi of Fig. 2.

Fig. 5 is a sideelevation showing the relative positions of the pistonand valve rod ends with the connected links in the second position ofFig. o 1 and in dotted lines in the succeeding position during a leftturn movement.

Under the usual conditions ci' manual operation, without my inventionthe wheel I0 mounted on the axle il is heldin aimed position or turnedas desired by the steering knuckle l2, steering arm I3 and steering rodpin it through the movement of the reach rod l5, ball joint pin I6,lever il about the fulcrum pin I3, gear i9 and worm 20 carried on thesteering post 2i in accordance with 15 the direction of movement of thesteering wheel 22 in the hands of the driver. In the heavier types ofcars having wide tread tires it has been found that this operationrequires the expenditure of a large amount of muscular force,particularly 20 when the car is not in motion, on account of thefrictional resistance between the tire treads and road surface at theirpoints of contact. In -fact the power required is sometimes greater thanthe driver can supply so that it is impossible to turn 25 'the Wheels atall.

In the particular form shown herein as one type of my invention, thedevice is connected in this steering system by disconnecting the reachrod I5 and the lever l1 .at the ball joint I6 and 30 interposing thecontrol lever 23 which is secured at an intermediate point in its lengthto the lower end of the lever Il by the fulcrum pin 2t through the holeformerly occupied by the ball joint pin I 8.

If this hole is tapered, a suitably tapered bushing 35 may be used toadapt it to receive the cylindrical bearing on the pin 24.

At the upper end of the control lever is attached the front end of thecontrol link 25 by means of the pin 26 and the rear end of the 40 `linkis hinged to the control rod head 21 by the pin 28. The control rod headis bored to receive the front end of the control rod 29 held in place bythe nut 30. The control rod extends horizontally to the rear and isadapted to receive a hollow extension 3| having the same outsidediameter as the control rod and is open at the rear end but closed atthe front end by the inserted end of the control rod.

The lower end of the lever 23 is hinged to the front end of the powerlink 32 by the pin IS to one end oi which the rear end of the reach `rodi5 is fastened by the usual ball joint. To fthe rear end of the powerlink is hinged the power rod head 33 by means of the pin 34. The rear 55portion of the power rod head forms a vertical transverse plate havingtwo vertically aligned horizontal cylindrical apertures, the lower oneadapted to receive the forward end of the power rod 35 to which it issecured by the nut 36 and the'upper one having a sliding fit about areduced portion of the forward end of the control rod 29 between thecontrol rod head 21 and a shoulder formed by the full diameter portionof the control rod at 29.

On the rear end of the power rod 35 is screwed the forward half of thepiston 31 to which .is fastened the rear half of the piston 31' bybolts38. The piston sections 31 and 31 carry packing rings 39 and 39respectively recessed in annular openings in their outer cylindricalsurfaces.

The piston s1, 31' nts the bore of the power cylinder 40 which is closedat the forward end by the plate 4I and at the rear by the plate 42. Infront of the plate 4| is bolted the pressure cylinder 43 of which thisplate forms the rear end and the front endly of cylinder 43 is closed bythe plate 44. To the rear of plate 42 is bolted the drainage cylinder 45of which that plate forms the front end and the rear end of cylinder 45is closed by the plate 46.

Aligned openings 41 in plate 42, 48 in the piston, 49 in plate 4| and 50in plate 44. are provided to permit the passage of the control rod 29through plates 44 and 4I and of the control rod extension 3| through thepiston and the plate 42.

Aligned openings 5I in plate 4| and 52 in plate 44 are also provided topermit the power rod 35 to slide through them.

'Ihe openings 41, 49, 50, 5| and 52 are provided with packing glands 53.

An opening into the lower portion of the pressure cylinder suchzas 54 isthreaded to receive the end of the pressure supply pipe 55 from thepressure reservoir` 56. Flow through this pipe may be controlled by avalve 55 if desired.

The drainage cylinder has an opening at the bottom such as 51 adapted toreceive a drain pipe 58 through which it may be emptied. If desired,this pipe may be connected to the inlet of a pressure pump 58' so thatthe contents may be discharged into the pressure reservoir 56 through asuitable check valve 58".

The power rod is centrally bored from its rear end forward to a pointwhich will always lie within the pressure cylinder 43 to form thepassage 59 which has an opening 60 at the bottom near the front endhaving an area at least equal to that of the cross section of the hole59, and is so positioned that it will always lie within the pressurecylinder 43. The rear end of the passage 59 opens into a passage 6Iformed in the,piston which has an upper opening into thepassage 48 inthe lower side thereof. When the power system is in equilibrium thisopening or pressure front is closed by the outer surface of the controlrod extension 3|. i

'The outer wall of the control rod extension has two horizontaidgrooves62 and 63 formed in its lower side separated by a distance equal to thethickness of the piston and so positioned that when the system is inequilibrium the groove or port 62 is entirely behind the rear face ofthe piston and the groove or port 63 is entirely in front of the frontface of the piston. The control rod extension 3| has a longitudinaldrainage bore 64 which is partially reduced opposite the ports 62 and 63so that there is no opening between the bore and these ports (see Figs.2 and 3). Above this restricted portionand between the ports 82 and 63there are two ports and 66 through the upper wall of the control rodextension which are closed by the upper wall of the opening 48.in.thepiston when the power' system is in equilibrium. (See Figs. `2 and 4.)The bore 64 is closed at the front end and open into the drainagecylinder 45.

In operation, using a liquid such as' oil for the pressure transmittingmedium, the pressure reservoir 56, pipe 55 and pressure cylinder 43 arelled with oil under pressure from a suitable source, the power cylinder40 is filled with oil on both sides of the piston and the drainagecylinder 45 is empty, and the parts of the device in the position'shownin full lines in Fig. I.

, Assuming that it is desired to turn the wheel I0 to make a left turn,the steering wheel 22 is turned in a counter-clockwise direction asusual, rotating the steering post 2| and the worm 20 in the samedirection. This causes the gear 20 ment of the pin 24 in the lower endof the arm 25 I1 causes the lever 23 to move about the pin I8 as afulcrum in a counter clockwise direction.

This forward movement brings the several port openings in the controlvalve extension and the piston into the relative positions shown in Fig.2 30V so that oil under pressure can pass from the cylinder 43 throughthe opening 6I| and the bore 58 in the power rod 35 and thence throughthe port 6I of the piston and the port 62 of the control rod extensioninto the rear chamber of the power cylinder 40. At the same time theport 65 is opened between the front chamber of the power cylinder 40 andthe drainage bore 64, allowing oil to escape from the front of the powercylinder into the drainage cylinder. unbalanced pressure in the rearchamber, the piston moves forward pushing the power rod 35 power link 32and ball joint pin I6 ahead so that the reach rod I5, pin I4, arm I3,knuckle I2 and axle II coact in the usual manner to turn the wheel I0 tothe left.v

If it is desired to effect this turning movement more rapidly than itwould normally occur under the impulse of the power piston alone,additional turning motion may be made with the steering 6 wheel whichwill cause a further forward movement of the-pin 24, pin 26, link 25,control rod head 21 and control rod 29 so that the shoulder 29' willcontact with the upper portion of the power rod head 33 and help to moveit forward, thus supplementing the motion imparted by the moving powerpiston.

While the counter clockwise rotation of the steering wheel is continuedthe pin 24 advances and holds the control rod and piston in the relativepositions shown in Fig. 2 as they move forward together through thepower cylinder.

When the steering wheel movement is stopped by the driver the lever 23and links 25 and 32 are in the relative positions shown in full lines inFig. 5. 'I'he pin 24 stops and becomes the fulcrum point for a clockwiserotation of the lever 23 moved forward at the bottom by the pressure inthe rear of the piston until the ports 62 and 65 are closed by thecombined forward motion of the A piston and rearward motion of thecontrol rod pin 28 so that the links and lever 23 take the relaf tivepositions shown in dotted lines in Fig. 5 as Under the influence of the40- the pressure on both sides of the piston becomes equalized.

A further turn to the left may be made by a. further counter clockwisemotion of the steering wheel within the mechanical limits of the frontwheel motion, repeating the same cycle of operations.

The front wheels may be turned to the right by turning the steeringwheel in a clockwise direction, thereby reversing the movements of thelinks and connected parts which then will coact to admit pressure to theforward end of the power cylinder through the ports 6| and 63 and drainthe oil from the rear end of the power cylinder through the-port S6 andthe drainage bore 64, causing a backward movement of the piston and theconnections to the wheel.

Due to the pressure exerted by the power cylinder I have found that theforce required to turn the steering wheel is greatly reduced, givingeasier control and causing less fatigue to the driver.

Since the motion of the wheels is limited by the movement of the powerpiston in a cylinder lled with oil, any shocks due to rough roadsurfaces, front tire blow outs etc., will be cushioned by the oil, thepower cylinder serving as a dash-pot and preventing sudden strains onthe steering wheel which might cause the driver to lose control of thedirection of the car.

In case the pressure should fail for any reason the car could still besteered in the usual manner of a hand controlled steering car withoutany change in the apparatus. To make a left turn, for instance, the samesequence of operations will obtain involving the forward movement of thecontrol rod 29 which then moves ahead until the shoulder 29' contactswith the upper portion of the power rod yoke 33 and both rods then moveforward together to move the reach rod l5 and the connected steeringrods to turn the front wheels to the left. In making a right turn thedesired eil'ect is obtained when the upper part of the power rod headcontacts with the rear face of the control rod head 21 to move the powerrod and connected parts rearwardly. While the operations allow a littlemore lost motion in the steering mechanism than when the pressure iseffective I have found that 'the total .lost motion is no greater thanthat usually considered desirable in manually steered cars.

It will thus be seen that my device permits the application of powercontrol to mechanisms making them fully responsive to comparativelylesser impulses from the normal controlling agency, with or withoutsupplementary action of the controlling agency and so arranged that incase v of the failure of the power source the amplitude, speed anddirection of the motion will be effected in a normal manner by thecontrolling agency without interruption, mechanical or electricaladjustments or volition of the operator.

I claim:

1. A power control device comprising a chamber containing a fluid powermedium under pressure, a closed power cylinder, a piston slidablymounted in said cylinder, a control rod mounted to reciprocate withinsaid chamber, piston and cylinder in a line parallel with their commonlongitudinal axis, stops formed on said control rod external of saidchamber and cylinder, a piston rod actuated by said piston through saidcylinder and said chamber and carrying an external projection coactingwith said stops on said control rod, means controlled by the relativemotion of said control rod and piston to admit said power medium toeither end of said cylinder at the same time that some of the contentsof the I other end of the cylinder is permitted to escape therefrom, acontrol link pivoted at one end to said control rod and at the oppositeend to a floating lever at one end thereof, a power link pivoted at oneend to said piston rod and at the opposite end to the other end of saidfloating lever and to the actuating rod of a controlled mechanism and acontrolling member pivotally connected to said floating lever betweenthe ends thereof.

2. In a power control device, a controlling element, a floating leverpivotally attached thereto, a power link pivotally attached to saidlever at one end, an operating element of a controlled mechanismconnected at the same end of said lever, a control link pivotallyconnected at the opposite' end of said lever, a power rod hinged to saidpower link, a lateral extension carried on said power rod having anaperture parallel therewith, a piston carried by said power rod havingan aperture aligned with that in said lateral extension, a closed powercylinder adapted to slidably receive said piston, a pressure cylindermounted adjacent said power cylinder, a control rod hinged to saidcontrol link and slidably mounted in said aligned apertures and havingspaced stops coacting with said extension to permit limited relativemovement between the control rod and the power rod, and means actuatedby movement of the control rod for admitting pressure from the pressurecylinder to either side of the piston at the same time that the powermedium is being exhausted from the opposite side of the piston.

WILLIAM O. TArr, JR.

